From owner-freebsd-hackers@FreeBSD.ORG  Wed Jun 25 08:46:11 2008
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 346A4106564A
	for <freebsd-hackers@freebsd.org>; Wed, 25 Jun 2008 08:46:11 +0000 (UTC)
	(envelope-from artis.caune@gmail.com)
Received: from an-out-0708.google.com (an-out-0708.google.com [209.85.132.240])
	by mx1.freebsd.org (Postfix) with ESMTP id ECD658FC16
	for <freebsd-hackers@freebsd.org>; Wed, 25 Jun 2008 08:46:10 +0000 (UTC)
	(envelope-from artis.caune@gmail.com)
Received: by an-out-0708.google.com with SMTP id b33so852935ana.13
	for <freebsd-hackers@freebsd.org>; Wed, 25 Jun 2008 01:46:10 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma;
	h=domainkey-signature:received:received:message-id:date:from:to
	:subject:mime-version:content-type:content-transfer-encoding
	:content-disposition;
	bh=X98L0xoMNEcgMHUOZEfRbjh+OXtNlTRhrdpawt1TQ9U=;
	b=kUm36eJwkEucNFa9hbh4TOC3tUxtKjAsH1c8xyHoRKMmtWjND27z2E1NISh1BlPOD8
	diKGOqn6bOhvW0ogLKXmSZ0vEFZ+tUHW6sBLI9/ZLDIys7sLoN2ioF4SbZjdRkriG/XD
	MCX9ENjaQ2QukvHvcObBGvGSHW0VUDtjlOadM=
DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma;
	h=message-id:date:from:to:subject:mime-version:content-type
	:content-transfer-encoding:content-disposition;
	b=sCW3mBH029S9CZqjvjPN17mnyqjASgJ+F7k7G3GxfaKnBLMNu2v5X4rKEw8JJUn7Ru
	R0mEkz82InfpnZmAiPJjUBdbe05Q3c/perThuO8X1v8iBgxzCqckAXnX1LFk3OcZr8q/
	fdIUA6vIu/a4pluuoHsSqEpHUhMfIljnb5sX4=
Received: by 10.100.41.1 with SMTP id o1mr17996623ano.10.1214382086971;
	Wed, 25 Jun 2008 01:21:26 -0700 (PDT)
Received: by 10.100.253.17 with HTTP; Wed, 25 Jun 2008 01:21:26 -0700 (PDT)
Message-ID: <9e20d71e0806250121i33bbdf07y2a5ce910e79a7b57@mail.gmail.com>
Date: Wed, 25 Jun 2008 11:21:26 +0300
From: "Artis Caune" <artis.caune@gmail.com>
To: freebsd-hackers@freebsd.org
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Subject: build stamps
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 25 Jun 2008 08:46:11 -0000

If you are making world or release twice from one source, you will get
some binaries and lot of libraries which differ because of time
stamps:
   # make buildworld
   # make installworld DESTDIR=/home/build1
   # rm -r /usr/obj/usr
   # make buildworld
   # make installworld DESTDIR=/home/build2

   # diff -r /home/build1 /home/build2


freebsd-update-server also make world twice to find out where those
build stamps are.

I tried to freeze clock on build box while repeating build process:
   # while true; do date -n 0000; sleep 0.5; done

and there were no differences between two builds.


Is there any harm if I build releases with frozen clock?
or maybe load kld module which replace gettimeofday syscall at build time?

thanks,
Artis